Closure for containers

ABSTRACT

A closure for a container having a rim surrounding an opening to be closed, the closure including a lid portion having a peripheral rim portion adapted to sealingly engage the rim of the container, and a peripheral ring portion extending from the rim portion of the lid portion and having a depending portion adapted to engage the rim of the container to hold the peripheral rim portion in sealing engagement with the container rim. The depending portion is formed with a multiplicity of separate flexible finger elements, each having an inwardly directed abutment portion which in use engages the rim of the container to hold the closure in the closed position, the fingers occupying in their as molded or neutral positions a position in which the abutment portions are in use at least partially engaged with the rim of the container.

FIELD OF THE INVENTION

This invention relates to closures for containers, and more particularly to closures for larger containers, such as larger volume paint cans. The invention is not restricted to such applications and is equally applicable to all containers including containers of small volume.

BACKGROUND OF THE INVENTION

Containers for larger volumes of paint are usually closed by a metal lid which sealingly engages the curl of the container and which is held in its closed position by a metal locking ring. Such locking rings are relatively expensive and are difficult to fit using standard can filling and scaling machines.

Plastic closures are easier to fit using such machines but are difficult to seal properly under all conditions, and are not sufficiently strong to allow stacking for storage and-transport.

Composite plastic/metal closures which overcome the above problems are to be found in the patent literature such as:

U.S. Pat. No. 3,930,589, which discloses a closure including a metal lid which sealingly engages the rim of the container and is held captive in a plastic ring having a depending skirt which engages a bead or curl on the container rim to hold the lid in sealed engagement with the container rim. While this closure is described as a pry-off closure, requiring the use of a tool to open the closure, this is primarily because the closure as illustrated is for small containers such as food jars which do not allow the user's fingers to manipulate the skirt to remove the closure. A closure of the design illustrated would be manually removable if scaled up to a size suitable for a large volume paint can and such an arrangement would address the issues of automated fitting and manual opening without a special tool.

Australian Patent Application 767,465, discloses a closure which is effectively a scaled-up version of the closure detailed above, and which is described as having a skirt which can be manually manipulated to remove the closure. While this closure similarly addresses the issue of automated fitting and manual removal, it may still be difficult to easily manually remove the closure due to the requirement that the skirt of the plastic ring must be sufficiently rigid to ensure that engagement of the skirt with the curl of the container maintains a proper seal between the lid and the rim of the container.

Australian Patent 2001285604 and Australian Innovation Patent 2004100207 both disclose closures having downwardly depending skirt portions which are divided into a multiplicity of fingers or abutments which are forced into engagement with part of the container by a locking ring member. The fingers or abutments are moulded or hinged so that the fingers or abutments are biased outwardly clear of the rim of the container in the released or unlocked position. A problem with such arrangements is that the fingers tend to force the locking ring upwardly and stretch the locking ring due to the outward flex load of the outwardly hinged fingers.

In the light of the above, it would therefore be desirable to provide a closure which allows automated fitting while maintaining a proper seal, but which does not suffer the problems caused by outward hinging as discussed above.

SUMMARY OF THE INVENTION

The invention provides a closure for a container having a rim surrounding an opening to be closed, the closure including a lid portion having a peripheral rim portion adapted to sealingly engage the rim of the container, a peripheral ring portion extending from the rim portion of the lid portion and having a depending portion adapted to engage the rim of the container to hold the peripheral rim portion in sealing engagement with the container rim, said depending portion being formed with a multiplicity of separate flexible finger elements each having an inwardly directed abutment portion which engages the rim of the container to hold the closure in the closed position, said fingers occupying in their as moulded or neutral positions a position in which the abutments are at least partially engaged with the rim of the container, and a locking ring surrounding the peripheral ring portion and being movable over the depending portion from a closed position in which the locking ring engages the depending portion to hold it in engagement with the rim, to an open position in which the depending portion is not constrained by the locking ring whereby the fingers cannot be flexed from their neutral positions to be disengaged from the rim to allow the closure to be removed by the application of a lifting force thereto.

It will be appreciated from the above that closures embodying the invention are able to be easily fitted to a container when the locking ring is in the open position, or as described below, with the locking ring in the closed position, while the locking ring provides sealing security for the closure, along the lines of the known metal locking ring, when the locking ring is in the closed position. By arranging the fingers in the locking position in their neutral state, the problems associated with fingers which are hinged outwardly are avoided.

As will be described further below, closures embodying the invention are able to be fitted in different ways, including one way in which the locking ring can be in the closed position.

It will be appreciated from the above that the fingers are configured to be free to flex to an open position, absent the action of the locking ring, by the application of a minimal lifting force to the closure.

To assist in removing the closure from a container, the locking ring may be formed with a handle projecting from the upper edge of the locking ring, and preferably shaped to occupy a rest position which does not project to any significant extent above the upper edge of the locking ring. To this end, the handle may be formed in a recess formed in the upper edge of the locking ring.

The abutments on the fingers are preferably formed with a deep locking undercut which increases the engagement between the abutments and the rim of the container to make the closure more secure. The portion of the rim of the container engaged by the undercut is usually in the form of a metal curl or its equivalent in the case of a moulded plastic container body.

The division of the skirt into separate fingers allows the fingers to be moulded with a deeper locking undercut than would be possible with a integral skirt. The separate fingers allow the deep locking undercut to be more easily demoulded.

Each finger element may be formed with one or more integral webs extending from the abutment portion to an inner face of the depending portion. This ensures that the abutment portion is relatively rigid whereby the flexing of the finger elements during removal of the closure occurs in the upper region of the peripheral ring portion.

Each of the finger elements may be formed with an outwardly projecting flange or stop member which defines the closed position of the locking ring, preventing the locking ring moving downwardly any further than the flange or stop member.

The locking ring flange or stop member is preferably formed with a downwardly projecting extension preferably strengthened by an inwardly projecting web which is shaped to assist in guiding the closure into engagement with a container during the closure applying process.

It will be appreciated that in the above arrangement, the neutral axis of the locking ring should be below the neutral axis of the rim of the container, which is usually in the form of a curl, in the closed position of the locking ring.

In one form the lid portion is made from a stronger material than the ring portion, the ring portion being sufficiently flexible to be disengaged from the rim of the container with minimal manual force absent the action of the locking ring, the lid portion being held in the ring portion to form a composite closure.

As mentioned above, while the composite closure defined above has particular application to containers or cans of larger volumes which require a stronger lid portion, the closure also may offer advantages in other applications in which the closure may be formed as a unitary moulding of the same plastic material. A closure formed as a unitary moulding may have application in relation to containers for dangerous goods in which sealing integrity is important.

Alternatively, the ring portion and the lid portion may be separately moulded from the same or different plastic materials, to form a composite plastic closure.

The lid portion may be a metal lid similar to the metal lids illustrated in the above patent literature and having a rim formed to sealingly engage the rim of the container with the assistance of a gasket or seal formed in the peripheral rim of the lid in a known manner.

Since the closure ring can be supplied separately to the lid portion and assembled during the closing process, the invention may further provide a closure ring for attachment to a lid portion having a peripheral ring portion adapted to sealingly engage the rim of a container, said closure ring having a depending portion adapted to engage the rim of the container to hold the peripheral ring portion in sealing engagement with the container rim, said depending portion being formed with a multiplicity of separate flexible finger elements each having an inwardly directed abutment portion which in use engages the rim of the container to hold the closure in the closed position, said fingers occupying in their as moulded or neutral positions a position in which the abutment portions are in use at least partially engaged with the rim of the container, and a locking ring surrounding the peripheral ring portion and being movable over the depending portion from a closed position in which the locking ring engages the depending portion to hold the depending portion in the rim engaging position to an open position in which the depending portion is not constrained by the locking ring and is free to be disengaged from the rim to allow detachment from the container.

The locking ring may be formed from the same plastic material as the closure ring and is configured with an inner camming surface which engages the outer surface of the depending portion in use to force the abutment portions into engagement with the rim or curl to securely hold the closure in its closed condition.

The closure ring and the locking ring may be formed as a unitary moulding with the locking ring in or slightly above the open position and held in this position by frangible elements connecting the locking ring to the closure ring. Thus after the closure has been fitted to a container, or before, as described below, the locking ring is pushed down either manually or by a machine to break the frangible elements and engage the skirt of the closure ring to hold the closure in its closed and sealed position.

The ring portion of the closure may be formed with a projecting element which engages a groove formed in the locking ring in the open position to allow the locking ring to resist detachment and to allow the locking ring to be used to lift the closure from the container.

Where the lid portion and ring portion are formed as an integral plastic moulding, the inner face of the lid portion may be covered by a barrier member to avoid the contents of the container penetrating the rim portion.

In another aspect, the invention provides a method of fitting a closure of the type defined above to a container having a rim adapted to be engaged by the closure to close the container, comprising positioning the lid portion in the ring portion, closing the locking ring and fitting the closure to the container, the locking ring flexing sufficiently to allow the abutments to engage the rim.

Each of the above defined aspects will be better understood in the light of the following embodiment which will now be described with reference to the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a closure embodying the invention in the closed position on a container;

FIG. 2 is a sectional elevation through the closure and container of FIG. 1 at a position remote from the handle on the closure;

FIG. 3 is an enlarged detail showing small undercuts on the fingers;

FIGS. 4 is a sectional elevation through the closure at the handle, with the closure locking ring in the open condition;

FIGS. 5 and 6 are sectional elevations illustrating two stages of the closure removal process, and

FIG. 7 is a view similar to FIG. 3 showing the closure in the as moulded condition.

DESCRIPTION OF EMBODIMENT

Referring to the drawings, the closure 1 includes a metal lid 2 having an upstanding peripheral rim 3 formed with a downwardly open channel 4 including a suitable gasket material 5 adapted to sealingly engage the curl 6 of a metal container 7 of know construction. The rim 3 of the lid 2 is received in a moulded plastic ring 8 having a channel-shaped cavity 8 a shaped to relatively loosely receive the rim 3. Thus, as distinct from the composite closures illustrated in the prior art detailed above, it is not important for the rim 3 to be held captive in the ring 8, provided it does not readily fall out of the ring 8 during normal handling prior to and during the fitting of the closure to the container 7.

The ring 8 further includes an inner skirt 9 having a flange 10 which engages the lid 2 adjacent the rim 3, and an outer skirt 11 depending from the channel 8 a to a position below the curl 6.

The outer skirt 11 is formed with a multiplicity of shaped fingers 12 each having an inwardly directed abutment 13 adapted to engage under the curl 6 in the closed position illustrated in FIG. 2, to hold the closure 1 in the closed position on the container 7. Each finger structure may be reinforced by integrally moulded webs 12 a as shown.

It will be noted that the abutments 13 on the fingers 12 have a deep locking undercut, which increases the security of the locking action between the abutments 13 and the curl 6. The division of the skirt into separate fingers allows the demoulding of the abutments of the configuration shown, which would not be possible with an integral skirt.

As mentioned earlier in the specification, and as shown in FIGS. 4 and 8, the fingers 12 are moulded to have a neutral position in which the abutments 13 engage the curl 6. This means that when the fingers are locked as described below, there is little or no outward flex load on the locking ring and the closure has a stable locked condition.

The fingers are held in the closed position illustrated by a locking ring 14 having an internal camming surface 15 which terminates in an inwardly directed flange 17, which sequentially engage the outer surfaces of the fingers to force the abutments 13 into engagement with the curl 6 as illustrated in FIG. 2. The locking ring 14 is upwardly movable from the closed position of FIG. 2 to the open position of FIG. 4, in which the camming surface 15 and flange 17 are positioned above the fingers 12, which are then free to flex outwardly as the abutments 13 engage the curl 6, to a position in which the abutments are free to flex around the curl 6 as the closure is manually lifted from the container 7, as illustrated in FIGS. 5 and 6. To assist in this regard, and to prevent the locking ring 14 becoming detached from the closure ring 8 in the open position of FIG. 4, the ring 8 is formed with a shaped abutment 16 which is engaged by the flange 17, which as illustrated in FIGS. 2 and 4, has a complementary shape designed to positively engage the abutment 16, as clearly illustrated in FIGS. 5 and 6. This enables the locking ring 14 to be gripped in the open position to lift the closure 1 off the container 7 in the manner shown in FIGS. 5 and 6.

The locking ring 14 is formed with an integral handle 21 to assist in opening the closure. The handle 21 is formed in a recess in the upper edge of the locking ring 14 so that it occupies the position illustrated when at rest. The handle is attached to the locking ring 14 by straps 21 a, each of which is formed with a groove 22 which allows the handle to be easily raised to a position more conducive to applying the appropriate lifting force to the locking ring.

During the lifting operation, the locking ring initially flexes and the upper portion of the locking ring disengages the skirt. Then as the locking ring is further lifted, the outward flex exerted on the fingers by their engagement with the curl sequentially raises the locking ring to allow the closure to be lifted off.

To prevent the locking ring 14 disengaging from the closure ring 8 when it is moved to the closed position, the fingers 11 are formed with outwardly extending stop members 18 which engages the flange 17 of the locking ring 14 when it reaches the closed position, as shown in FIG. 2. The locking ring 14 is designed to have a neutral axis which is positioned below the neutral axis of the curl 6 when the locking ring 14 is in the closed position of FIG. 2, to ensure that the locking ring 14 remains in the closed position when moved to that position.

To assist in locating the closure on a container, at least several of the stop member 18, and preferably all of the stop members 18, are formed with a downward extension 19 and a reinforcing web 20 shaped as shown to assist in locating the closure on the container and guiding the closure over the curl 6 of the container during the closure fitting operation.

Some of the fingers 12 have small undercuts 12 b (FIG. 3) which provide some resistance against the locking ring 14 moving from the locked position in the absence of a sufficient applied force. This reduces the likelihood of inadvertent opening during handling and transport. The undercuts 12 b are omitted in the three fingers 12 located at the position of the handle 21 to reduce the resistance to opening in this region. The undercuts 12 b are formed on the next fingers 12 and then on every second finger 12 around the periphery of the closure.

To allow better finger access to the flange 17 of the locking ring 14, in the event that a handle is not provided, and to enable the ring to be more readily lifted towards the open position, selected fingers 12 may be moulded without stop members (not shown), or selected stop members 18 may be moulded with frangible connections (not shown) to the fingers 12 to enable the selected stop members to be removed if necessary.

The closure ring 8 and the locking ring 14 may be formed as a unitary moulding with the locking ring 14 just above the open position as shown in FIG. 7. The locking ring 14 is connected to the closure ring 8 by frangible elements 19 which are broken when the locking ring 14 is first moved to the closed position after fitting to a container 7 to be closed. The closure 1, as formed is capable of being fitted to a container by known automated closing apparatus with minimal modification of the apparatus.

The fitting of the closure to a container can be achieved in several different ways. For example the metal lid 2 can be positioned on the rim 6 of the container and the closure ring 8 fitted over the rim 3 of the lid, whereupon the locking ring 14 is pushed to the closed position either manually or by the use of known automated machinery. Alternatively, the closure ring 8 may be fitted to the rim 3 of the lid 2 and the assembly positioned on the rim 6 of the container, whereupon the locking ring is pushed to the closed position as before.

In a further and preferred alternative, it has surprisingly been found that the closure ring 8 and lid 2 can be fitted to a container rim with the locking ring 14 in the closed position, the ring 14 stretching enough during this operation to allow the abutments 13 to flex outwardly to engage the curl 6, but without damaging the closure. In this case the closure 1 could be supplied to the user fully assembled ready for automated fitting by known machinery.

To assist in automated closing, the closure ring 8 is formed with an upstanding bead 25 on its upper shoulder. This ensures that the force applied to the closure 1 by the closing machine is shared by the bead 25 and the upper edge 26 of the ring 8.

When the closure has been opened and the contents partially used, the container can be resealed by fitting the closure to the rim of the container with the locking ring up and then pushing the locking ring down to lock the closure in the closed condition. The opening and closing process can be repeated as many times as necessary while the container is in use.

It will be appreciated from the above that the closure 1 provides a function similar to the known metal locking ring without the disadvantages detailed above. The closure 1 furthermore allows opening without the need for the user to manually manipulate the skirt, as is required in some of the prior art closures described above. 

1. A closure for a container having a rim surrounding an opening to be closed, the closure including a lid portion having a peripheral rim portion adapted to sealingly engage the rim of the container, a peripheral ring portion extending from the rim portion of the lid portion and having a depending portion adapted to engage the rim of the container to hold the peripheral rim portion in sealing engagement with the container rim, said depending portion being formed with a multiplicity of separate flexible finger elements each having an inwardly directed abutment portion which in use engages the rim of the container to hold the closure in the closed position, said fingers occupying in their as moulded or neutral positions a position in which the abutment portions are in use at least partially engaged with the rim of the container, and a locking ring surrounding the peripheral ring portion and being movable over the depending portion from a closed position in which the locking ring engages the depending portion to hold it in engagement with the rim, to an open position in which the depending portion is not constrained by the locking ring whereby the fingers can be flexed from their neutral positions to be disengaged from the rim to allow the closure to be removed by the application of a lifting force thereto.
 2. The closure of claim 1, wherein the finger elements are configured to flex to an open position. absent the action of the locking ring, by the application of a minimal lifting force to the closure.
 3. The closure of claim 1, wherein the abutment on the finger elements are formed with a deep locking undereut which increases the engagement between the abutment portions and the rim of the container to make the closure more secure.
 4. The closure of claim 3, wherein each abutment portion is reinforced by at least one integral web extending from the abutment portion to an inner face of the depending portion.
 5. The closure of claim 1, wherein at least some spaced ones of said finger elements are formed with an outwardly projecting flange or stop member which defines the closed position of the locking ring, preventing the locking ring moving downwardly any further than the flange or stop member.
 6. The closure of claim 5, wherein at least some spaced ones of said flanges on said finger element is formed with an integral downward extension reinforced by an integral web shaped to assist in locating the closure on a container.
 7. The closure of claim 1, wherein the lid portion is made from stronger material than the ring portion, the ring portion being sufficiently flexible to be disengaged from the rim of the container with minimal manual force absent the action of the locking ring, the lid portion being held in the ring portion to form a composite closure.
 8. The closure of claim 1, wherein the lid portion is moulded from the same or a different plastic to the ring portion.
 9. The closure of claim 1, wherein the lid portion and the ring portion are formed as an integral plastic moulding.
 10. The closure of claim 1, wherein the locking ring is formed with an integral handle to assist in moving the locking ring to the open portion.
 11. The closure of claim 1, wherein the ring portion is formed with a projecting element which engages a groove formed in the locking ring in the open position to allow the locking ring to resist detachment and to allow the locking ring to be used to lift the closure from the container.
 12. A closure ring for attachment to a lid portion having a peripheral rim portion adapted to sealingly engage the rim of a container, said closure ring having a depending portion adapted to engage the rim of the container to hold the peripheral rim portion in sealing engagement with the container rim, said depending portion being formed with a multiplicity of separate flexible finger elements each having an inwardly directed abutment portion which engages the rim of the container to hold the closure in the closed position, said fingers occupying in their as moulded or neutral positions a position in which the abutments are at least partially engaged with the rim of the container and a locking ring surrounding the peripheral ring portion and being movable over the depending portion from a closed position in which the locking ring engages the depending portion to hold the depending portion to the rim engaging position to an open position in which the depending portion is not constrained by the locking ring and is free to be disengaged from the rim to allow detachment from the container.
 13. A method of fitting a closure according to claim 1 to a container having a rim adapted to be engaged by the closure to close the container, comprising positioning the lid portion in the ring portion. closing the locking ring and fitting the closure to the container, the locking ring flexing sufficiently to allow the abutment portions to engage the rim of the container. 